303006-90-8Relevant articles and documents
Effective Synthesis of Ladder-type Oligo(p-aniline)s and Poly(p-aniline)s via Intramolecular SNAr Reaction
Wang, Hui,Zhao, Hongchi,Chen, Shuang,Bai, Libin,Su, Zhiyi,Wu, Yonggang
, p. 2217 - 2221 (2021)
Symmetric ladder-type oligo(p-aniline)s and poly(p-aniline)s were successfully synthesized by an intramolecular ring closure in a highly efficient SNAr reaction from oligo(p-phenylene)s and poly(p-phenylene)s with fluorine (F) and secondary amine (NH) groups. Unlike Cadogan ring closure, the newly designed cyclization reaction will not produce a mixture of symmetric and nonsymmetric structures. Moreover, the introduction of the F atom does not hinder Suzuki polymerization. The result indicates that preparing regular oligomers and polymers with a nitrogen bridge is possible.
Mechanistic Origins of Regioselectivity in Cobalt-Catalyzed C(sp2)-H Borylation of Benzoate Esters and Arylboronate Esters
Chirik, Paul J.,MacMillan, Kaitlyn T.,Pabst, Tyler P.,Quach, Linda
supporting information, (2021/01/06)
Carbon–hydrogen (C–H) bonds are ubiquitous in organic molecules, and methods for their selective functionalization to more reactive functional groups is a long-standing goal in catalysis, as applied to organic synthesis. Of the established methods involving transition metal catalysts, many employ carefully engineered substrate-catalyst interactions, placing the targeted C–H bond proximal to the metal catalyst, resulting in activation and subsequent functionalization. Here, we report mechanistic investigations describing a conceptual alternative to this approach whereby a cobalt-based borylation catalyst differentiates between subtle electronic differences in C(sp2)-H bonds of benzoate esters and arylboronate esters. These advances motivate studies of catalysts that rely on inherent differences in C–H bond electronics to distinguish chemically inequivalent sites, providing a new tool for organic synthesis. Synthetic and mechanistic investigations into the C(sp2)-H borylation of various electronically diverse arenes catalyzed by bis(phosphine)pyridine (iPrPNP) cobalt complexes are reported. Borylation of various benzoate esters and arylboronate esters gave remarkably high selectivities for the position para to the functional group; in both cases, this regioselectivity was found to override the ortho-to-fluorine regioselectivity, previously reported for (iPrPNP)Co borylation catalysts, which arises from thermodynamic control of C(sp2)-H oxidative addition. Mechanistic studies support pathways that result in para-to-ester and para-to-boronate ester selectivity by kinetic control of B-H and C(sp2-H) oxidative addition, respectively. Borylation of a particularly electron-deficient fluorinated arylboronate ester resulted in acceleration of C(sp2)-H oxidative addition and concomitant inversion of regioselectivity, demonstrating that subtle changes in the relative rates of individual steps of the catalytic cycle can enable unique and switchable site selectivities. Most strategies to selectively activate and functionalize a specific C–H bond in an organic molecule rely upon carefully engineered spatial interactions between a substrate and a transition metal catalyst. Here, we report a conceptually distinct alternative strategy, whereby a cobalt catalyst distinguishes between subtly different C(sp2)-H sites of an arene based on electronics rather than sterics. Mechanistic studies elucidated the origins of substrate-controlled regioselectivity in the C(sp2)-H borylation of benzoate esters and arylboronate esters.
Nitrogen-containing heterocyclic compound and use thereof
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Paragraph 0128-0129, (2021/11/02)
[Problem] to provide a nitrogen-containing heterocyclic compound which emits technology and its use. [Solution] a nitrogen-containing heterocyclic compounds, wherein: (1) a compound represented Cz a-L-a Ar [formula (1) in, the Cz, (2) the formula:(In the
Selective Photocatalytic C-F Borylation of Polyfluoroarenes by Rh/Ni Dual Catalysis Providing Valuable Fluorinated Arylboronate Esters
Tian, Ya-Ming,Guo, Xiao-Ning,Kuntze-Fechner, Maximilian W.,Krummenacher, Ivo,Braunschweig, Holger,Radius, Udo,Steffen, Andreas,Marder, Todd B.
supporting information, p. 17612 - 17623 (2019/01/04)
A highly selective and general photocatalytic C-F borylation protocol that employs a rhodium biphenyl complex as a triplet sensitizer and the nickel catalyst [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the C-F bond activation and defluoroborylation process is reported. This tandem catalyst system operates with visible (blue, 400 nm) light and achieves borylation of a wide range of fluoroarenes with B2pin2 at room temperature in excellent yields and with high selectivity. Direct irradiation of the intermediary C-F bond oxidative addition product trans-[NiF(ArF)(IMes)2] leads to very fast decomposition when B2pin2 is present. This destructive pathway can be bypassed by indirect excitation of the triplet states of the nickel(II) complex via the photoexcited rhodium biphenyl complex. Mechanistic studies suggest that the exceptionally long-lived triplet excited state of the Rh biphenyl complex used as the photosensitizer allows for efficient triplet energy transfer to trans-[NiF(ArF)(IMes)2], which leads to dissociation of one of the NHC ligands. This contrasts with the majority of current photocatalytic transformations, which employ transition metals as excited state single electron transfer agents. We have previously reported that C(arene)-F bond activation with [Ni(IMes)2] is facile at room temperature, but that the transmetalation step with B2pin2 is associated with a high energy barrier. Thus, this triplet energy transfer ultimately leads to a greatly enhanced rate constant for the transmetalation step and thus for the whole borylation process. While addition of a fluoride source such as CsF enhances the yield, it is not absolutely required. We attribute this yield-enhancing effect to (i) formation of an anionic adduct of B2pin2, i.e., FB2pin2-, as an efficient, much more nucleophilic {Bpin-} transfer reagent for the borylation/transmetalation process, and/or (ii) trapping of the Lewis acidic side product FBpin by formation of [F2Bpin]- to avoid the formation of a significant amount of NHC-FBpin and consequently decomposition of {Ni(NHC)2} species in the reaction mixture.
A containing different conjugate bridge of the binuclear platinum (II) complex near-infrared phosphorescence material synthesis and application of (by machine translation)
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Paragraph 0056; 0059; 0060, (2017/12/27)
The invention discloses a conjugate bridge containing different of the binuclear platinum (II) complex near-infrared phosphorescent material and its in the organic electroluminescent diode in the application. Such a binuclear platinum complex near-infrare
Preparing (Multi)Fluoroarenes as Building Blocks for Synthesis: Nickel-Catalyzed Borylation of Polyfluoroarenes via C-F Bond Cleavage
Zhou, Jing,Kuntze-Fechner, Maximilian W.,Bertermann, Rüdiger,Paul, Ursula S. D.,Berthel, Johannes H. J.,Friedrich, Alexandra,Du, Zhenting,Marder, Todd B.,Radius, Udo
supporting information, p. 5250 - 5253 (2016/05/19)
The [Ni(IMes)2]-catalyzed transformation of fluoroarenes into arylboronic acid pinacol esters via C-F bond activation and transmetalation with bis(pinacolato)diboron (B2pin2) is reported. Various partially fluorinated arenes with different degrees of fluorination were converted into their corresponding boronate esters.
Optimizing sensitization processes in dinuclear luminescent lanthanide oligomers: Selection of rigid aromatic spacers
Lemonnier, Jean-Francois,Guenee, Laure,Beuchat, Cesar,Wesolowski, Tomasz A.,Mukherjee, Prasun,Waldeck, David H.,Gogick, Kristy A.,Petoud, Stephane,Piguet, Claude
experimental part, p. 16219 - 16234 (2011/12/01)
This work illustrates a simple approach for optimizing the lanthanide luminescence in molecular dinuclear lanthanide complexes and identifies a particular multidentate europium complex as the best candidate for further incorporation into polymeric materials. The central phenyl ring in the bis-tridentate model ligands L3-L5, which are substituted with neutral (X = H, L3), electron-withdrawing (X = F, L4), or electron-donating (X = OCH 3, L5) groups, separates the 2,6-bis(benzimidazol-2-yl)pyridine binding units of linear oligomeric multi-tridentate ligand strands that are designed for the complexation of luminescent trivalent lanthanides, Ln(III). Reactions of L3-L5 with [Ln(hfac)3(diglyme)] (hfac- is the hexafluoroacetylacetonate anion) produce saturated single-stranded dumbbell-shaped complexes [Ln2(Lk)(hfac)6] (k = 3-5), in which the lanthanide ions of the two nine-coordinate neutral [N 3Ln(hfac)3] units are separated by 12-14 A. The thermodynamic affinities of [Ln(hfac)3] for the tridentate binding sites in L3-L5 are average (6.6 ≥ log(β2,1Y,Lk) ≥ 8.4) but still result in 15-30% dissociation at millimolar concentrations in acetonitrile. In addition to the empirical solubility trend found in organic solvents (L4 > L3 ? L5), which suggests that the 1,4-difluorophenyl spacer in L4 is preferable, we have developed a novel tool for deciphering the photophysical sensitization processes operating in [Eu2(Lk)(hfac) 6]. A simple interpretation of the complete set of rate constants characterizing the energy migration mechanisms provides straightforward objective criteria for the selection of [Eu2(L4)(hfac)6] as the most promising building block.
Syntheses and 1H NMR spectroscopy of rigid, cofacially aligned, porphyrin-bridge-quinone systems in which the interplanar separations between the porphyrin, aromatic bridge, and quinone are less than the sum of their respective van der waals ra
Iovine,Kellett,Redmore,Therien
, p. 8717 - 8727 (2007/10/03)
Unusually rigid π-stacked porphyrin-spacer-quinone systems have been synthesized using an approach that enables extensive control over the nature of electronic interactions between donor, aromatic spacer, and acceptor. This new class of porphyrin-based st
